Axial Gap Dynamoelectric Machine

ABSTRACT

An axial gap dynamoelectric machine is provided with a stator core in which continuously wound coils ( 10   a,    10   d,    10   g,    10   j ) including a plurality of coils formed of continuously wound insulation-coated conductor wire are disposed in a circumferential direction with the continuously wound coils of the three phases overlapped. With the respective coils being disposed in a radiating shape, the continuously wound coils are configured so that on the inner diameter side of the coils, the insulation-coated conductor wires are continuously wound to adjacent coils via crossover wires ( 15 U 2, 15 U 3, 15 U 4, 15 U 5 ), and the coils are bent in the vertical direction and the continuously wound coils of each phase are made to overlap with each other so that the length (2×L 3 +L 2 ) of the crossover wires can be adjusted regardless of the core layer thickness (L 1 ) of the stator core. This configuration makes it possible to reduce copper loss, achieve a price reduction and improve durability, insulation properties and cooling performance of the axial gap dynamoelectric machine.

TECHNICAL FIELD

The present invention relates to an axial gap dynamoelectric machineused as a motor or a dynamo or the like.

BACKGROUND ART

In recent years, as global warming is becoming more and more serious,there is a growing demand for more energy-saving electric apparatuses.Power consumption by motors accounts for approximately 55% of annualpower consumption in Japan, and therefore there is currently a highlevel of attention to highly efficient motors. Designs using rare earthmagnets having a high energy product have been adopted so far to attainhighly efficient motors.

However, prices of Nd (neodymium) and Dy (dysprosium) which are rawmaterials of rare earth magnets are rising in recent years due to theexport ceiling control by China which is the world's largest producer.The export control policy by China is intended to prevent environmentaldestruction caused by extraction of Nd and Dy, and rising prices of rareearths and supply shortage are likely to continue in the future.

For this reason, axial gap motors are getting attention as one of meanscapable of realizing highly efficient motors using only ferrite magnetsinstead of rare earth magnets. Axial gap motors allow a wider magnetarea to be secured than conventional radial gap ones, and can therebycompensate for deterioration in holding power when rare earth magnetsare replaced by ferrite magnets and achieve efficiency equivalent to orhigher than conventional efficiency.

An axial gap motor is configured in various combinations such as1-rotor/2-stator type, 2-rotor/1-stator type and 1-rotor/1-stator type.

Patent Literature 1 described below shows a configuration in which fourcoils of the same phase are continuously wound and an axial gap motor(1-rotor/1-stator type) is formed using a Y-connection, and which isintended to reduce the motor price by reducing the number of connectionpoints using the continuous winding. Moreover, by gathering crossoverwires for connecting the coils on the inner diameter side of the coils,the coil outside diameter side is used as a free space and coolingperformance is improved by causing the coil outside diameter side tocontact the motor housing.

FIG. 9 shows a winding device for manufacturing conventional fourcontinuously wound coils corresponding to one phase.

In this winding device, four winding bobbins are arranged in a line andmounted in split core back-and-forth adjustment mechanisms 21 a, 21 b,21 c and 21 d that drive these bobbins back and forth. FIG. 9 describes,as an example, a state after completing winding of up to a third coreand immediately before starting winding of a fourth core.

A nozzle 24 a that supplies an insulation-coated conductor wire has amechanism for transfer in three axial directions, can form inter-corecrossover wires, and in this example, suppose the nozzle 24 a is fixedand winding is performed by rotating an entire winding portion includinga work. It goes without saying, however, that similar four continuouscoils can be formed using a scheme in which the nozzle is rotated.

After completion of winding of the third core, the split coreback-and-forth adjustment mechanism 21 c is made to retreat asillustrated, the split core back-and-forth adjustment mechanism 21 dequipped with an empty bobbin is then made to move forward by a distancethat a winding path can be secured. At this time, a crossover wire 25U4is fixed by fixing pins 22 e and 22 f, but to secure the winding path,the split core back-and-forth adjustment mechanism 21 d needs to move ata stroke equal to or greater than a core layer thickness L1 of eachcore, and therefore the length of the crossover wire 25U4 is at leastthe core layer thickness L₁ or more.

Once the crossover wire 25U4 is fixed by the fixing pins 22 e and 22 f,by rotating the entire winding portion around the split coreback-and-forth adjustment mechanism 21 d as a center, it is possible towind the insulation-coated conductor wire around the bobbin.

After completion of winding, the wire is cut at an end of the winding,the split core back-and-forth adjustment mechanism 21 d is made toretreat to its original position and the winding is thereby completed.At this time, the crossover wire 25U4 is detached from the fixing pins22 e and 22 f as with the crossover wires 25U2 and 25U3, and remainsfloating.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Laid-Open Publication No.2008-172859

SUMMARY OF INVENTION Technical Problem

After completion of the winding corresponding to the four cores, when acase of assembling a dynamoelectric machine is assumed as will bedescribed later using FIG. 4, if the core layer thickness of the statorcore is the length of the crossover wire in the diameter direction isL₃, and the length in the circumferential direction is L₂, an ideallength L of the crossover wire is 2×L₃+L₂.

However, as described above, since the length of the crossover wire isinevitably the core layer thickness L₁ or more due to a minimum strokeof the split core back-and-forth adjustment mechanism in the windingdevice, if this length is greater than 2×L₃+L₂, an excess portion isgenerated, which causes mutual interference, making it difficult toassemble the four continuously wound coils corresponding to threephases. From the standpoint of providing a dynamoelectric machine withhigh output, when the length L₃ of the crossover wire in the diameterdirection and the length L₂ of the crossover wire in the circumferentialdirection are minimized or the core layer thickness L₁ is increased toincrease the lamination factor by applying high-density winding to eachcoil, there has been a problem that the excess portion of the crossoverwire increases significantly, the crossover wires cause interferencewhen continuously wound coils are created and assembled around theshaft, making assembly extremely difficult or causing durability orinsulation properties to deteriorate.

It is therefore an object of the present invention to provide an axialgap dynamoelectric machine capable of simply assembling, in an axialdirection, a continuously wound coil densely wound with aninsulation-coated conductor wire, reducing copper loss and reducing theprice of the dynamoelectric machine by optimizing the length andarrangement of crossover wires, improving durability and insulationproperties, and further improving cooling performance.

Solution to Problem

In order to attain the object described above, an axial gapdynamoelectric machine of the present invention is provided with astator core in which continuously wound coils including a plurality ofcoils formed of continuously wound insulation-coated conductor wire aredisposed in a circumferential direction with the continuously woundcoils of three phases overlapped, in which with the respective coilsbeing disposed in a radiating shape, the continuously wound coils areconfigured so that on the inner diameter side of the coils, theinsulation-coated conductor wires are continuously wound to adjacentcoils via crossover wires, and the coils are bent in a verticaldirection and the continuously wound coils of each phase are made tooverlap with each other so that the length of the crossover wires can beadjusted regardless of the core layer thickness of the stator core.

When each coil is bent in the vertical direction and continuously woundcoils of each phase are overlapped with each other, if neutral pointswhich are winding start ends of the insulation-coated conductor wires ineach phase are arranged so as to be adjacent to each other in the innercircumference of the stator core, it is possible to integrate connectionpoints into one point and further reduce the price of the motor.

The length of the crossover wire is adjusted using the fixing pinsprovided in a winding jig that holds each cons in a radiating shape, andit is thereby possible to construct the crossover wire having an optimumshape and length.

When bending each coil in the vertical direction and causing thecontinuously wound coils in each phase to overlap with each other, thecrossover wire of the continuously wound coil in the circumferentialdirection is formed into an arc shape, and it is thereby possible tokeep the distance constant in the diameter direction between therotation shaft of the rotor and the crossover wire and further improveinsulation properties.

Furthermore, when each coil is bent in the vertical direction and thecontinuously wound coils in each phase are caused to overlap with eachother, the crossover wires in each phase are disposed so as not to causeinterference, and it is thereby possible to secure the spatialinsulation distance.

Advantageous Effects of Invention

As described above, according to the present invention, in order toprovide a dynamoelectric machine with higher output, even when thelength of the crossover wires in the diameter direction and length inthe circumferential direction are minimized or the core layer thicknessis maximized, it is possible to adjust the length of the crossover wiresregardless of the core layer thickness of the stator core to increasethe occupancy by densely winding a wire, and thereby reduce the price ofthe axial gap dynamoelectric machine, reduce copper loss, improvecooling performance and further increase durability and reliability.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating an arrangement of crossoverwires of coils in each phase of a motor with a 12-slot motor which is anembodiment of the present invention.

FIG. 2 is a connection wiring diagram of coils in each phase of a12-slot motor which is an embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating an arrangement of fourcontinuously wound coils of a U phase which is the embodiment of thepresent invention.

FIG. 4 is a perspective view illustrating an arrangement of the fourcontinuously wound coils of a U phase which is the embodiment of thepresent invention.

FIG. 5 is a perspective view illustrating an arrangement of the fourcontinuously wound coils of a U phase which is the embodiment of thepresent invention when the core layer thickness is greater than thelength of the crossover wires.

FIG. 6 is a perspective view illustrating a configuration of a windingdevice for manufacturing four continuously wound coils corresponding toone phase, which is the embodiment of the present invention, alsoapplicable to a case where a core layer thickness is greater than thelength of the crossover wire.

FIG. 7 is a diagram illustrating each coil of the four continuouslywound coils corresponding to one phase, which is the embodiment of thepresent invention, with each coil turned back by 90° vertically withinthe vertical plane in the diameter direction using the crossover wire asa reference.

FIG. 8 is a cross-sectional view of a first coil at the start of windingillustrating crossover wires of the continuously wound coilscorresponding to two phases, which is the embodiment of the presentinvention, tilted in advance at different angles in the axial directionand the four continuously wound coils corresponding to three phasesassembled in the axial direction.

FIG. 9 is a perspective view illustrating a conventional winding devicefor manufacturing four continuously wound coils corresponding to onephase.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment will be described with reference to theaccompanying drawings.

Embodiment

FIG. 1 schematically illustrates an arrangement of crossover wires ofcoils of each phase of a 12-slot motor, which is an embodiment of thepresent invention. The “crossover wire” referred to here is defined as aname of an insulation-coated conductor wire portion that connectsneighboring coils of continuously wound coils (FIG. 1 shows fourcontinuously wound coils).

An axial gap motor 100 is provided with a stator core 1 as a statorconfigured by arranging in a ring shape, four coils withinsulation-coated conductor wires continuously wound around an iron core3, in which a rotor 2 is disposed above and/or below the stator core 1.The rotor 2 is connected to a rotation shaft (not shown) disposed at acenter and is disposed at a certain distance from the stator core 1.Though not shown, magnets are disposed in the circumferential directionwith the N pole and S pole placed alternately on the stator core side ofthe rotor 2. Note that the axial gap motor 100, which will be describedbelow, is an example, and it goes without saying that the number ofcoils in each phase, that is, the number of slots can be changed asappropriate.

In the embodiment in FIG. 1, four U-phase coils 10 a, 10 d, 10 g and 10j are continuously wound by a winding device, which will be describedlater using FIG. 6, via crossover wires. Note that the winding directionof the coils is the same for all the coils and all the crossover wiresare integrated on the inner diameter side of the coils.

The four V-phase coils 10 b, 10 e, 10 h and 10 k and the four W-phasecoils 10 c, 10 f, 10 i and 10 l also have the same winding direction ofcontinuously wound wires and the same arrangement of crossover wires.

By arranging terminal wires which are wiring starting ends of the fourU-phase continuously wound coils, four V-phase continuously wound coilsand four W-phase continuously wound coils in mutually neighboringpositions and connecting these three phase terminal wires via connectionterminals or by welding, it is possible to cause the connected part tofunction as a neutral point 5.

As a result, it is possible to reduce the number of connection points toone point and thereby reduce the motor price.

By integrating all the crossover wires on the coil inner diameter side,the coil outside diameter side becomes a free space, and it is possibleto improve cooling performance of the motor, for example, by making thecoil outside diameter side contact the motor housing. Furthermore, sincerespective input wires 4 of the four U-phase continuously wound coils,four V-phase continuously wound coils and four W-phase continuouslywound coils can be necessarily arranged at neighboring positions, it ispossible to guide these input wires so as not to contact the rotor 2 andlead them out of a motor case and thereby cause the stator core 1 tofunction as a stator.

FIG. 2 illustrates a wire connection diagram of the stator core 1 in theaxial gap motor 100 of the present embodiment.

A U-phase coil 10U is configured by connecting an input wire 15U1, coil10 a, crossover wire 15U2, coil 10 d, crossover wire 15U3, coil 10 g,crossover wire 15U4, coil 10 j and terminal wire 15U5. The coil windingdirection is the same for all the coils. The configuration as well asthe coil winding direction is also the same for the V-phase coil 10V andW-phase coil 10W.

That is, the axial gap motor 100 of the present embodiment is made up ofa four-series Y-connection using three sets of four continuously woundcoils. As described above, the stator core functions as a stator byconnecting a central point (N) of the U-phase coil 10U, V-phase coil 10Vand W-phase coil 10W as a neutral point.

In order to illustrate the structure and arrangement of each fourcontinuously wound coil, FIG. 3 shows a schematic diagram and FIG. 4shows a perspective view using the coil U phase as an example. It goeswithout saying that the V-phase coil 10V and the W-phase coil 10W alsohave the same structure and arrangement.

Here, when a core layer thickness of the stator core 1 is L₁, a lengthin a diameter direction of the crossover wire is L₃, and a length in acircumferential direction thereof is L₂, and the circumferentialdirection of the crossover wire is assumed to be disposed along theouter circumference of the rotation shaft of the dynamoelectric machinelocated at the center, an ideal length L of the crossover wire is2×L₃+L₂ as is obvious from FIG. 4.

By forming, in advance, the circumferential direction of the crossoverwire in an arc shape, it is possible to bend the four continuously woundcoils corresponding to three phases in the vertical direction andassemble them in the axial direction centered on the rotation shaft.

Furthermore, as shown in FIG. 1, in areas where crossover wires crosseach other between neighboring U phase and V phase, between neighboringV phase and W phase and between neighboring W phase and U phase, bysetting the crossover wires 15U2, 15V2 and 15W2 to different angles withrespect to the axial direction of the rotation shaft (15U2 is set to behorizontal, 15V2 is set at angle φ1 and 15W2 is set at angle φ2 in FIG.8) as shown in the example in FIG. 8, it is possible to preventinterference of wires in the intersection of crossover wires, preventthe wires from contacting each other and reliably prevent short circuitsof the wires.

FIG. 6 shows an example of a winding device for realizing an ideallength of the crossover wire when creating four continuously wound coilscorresponding to one phase.

Four winding bobbins are arranged at intervals of approximately 90° inthe circumferential direction with respect to a winding jig 31. Supposethe central axis of rotation of winding is substantially perpendicularto the axis of rotation of the winding jig 31.

Note that the number of winding bobbins is not limited to four, but canbe changed depending on the number of coils of each phase and the angleinterval in the circumferential direction may be set so as to adapt tothe change.

Here, as in the case of FIG. 9, a case will be described as an examplewhere winding of up to a third core is completed and winding of a fourthcore is started. In this example, a nozzle 24 b that supplies aninsulation-coated conductor wire has a mechanism for transfer in threeaxial directions, so that it can form a crossover wire in any givendirection when starting winding onto the next bobbin.

After completion of winding of the third core, the winding jig 31 ismade to rotate by 90° around the vertical axis and an empty bobbin iscaused to protrude on the axis of rotation of a winding support section36. At this time, a crossover wire 35U4 is fixed by fixing pins 32 e and32 f with a transfer of the nozzle 24 b, and wiring of the fourth coreis made possible by causing the whole wiring section to rotate around asplit core 30 j. After completion of the wiring, the winding end wire iscut and the wiring is thereby completed. At this time, the crossoverwires 35U2, 35U3 and 35U4 are not detached from the fixing pins and canmaintain their desired shapes.

Thus, since the winding bobbins are arranged in a radiating shape, anywinding bobbin does not interfere with other winding bobbins during thewinding and high-density winding is thereby made possible, and it isalso possible to form crossover wires between the roots of theneighboring winding bobbins, and reduce the length L of the crossoverwires regardless of the core layer thickness L₁ of the stator coreunlike the prior art in which the length L of the crossover wiresinevitably become the core layer thickness L₁ or more.

That is, by adjusting the pin shape and arrangement positions of thefixing pins 32 e and 32 f, it is possible to set the length L of thecrossover wires to an ideal length of the crossover wires of 2×L₃+L₂ asshown in FIG. 4 and further form the crossover wires into an arc shapeby arranging a plurality of fixing pins on the circumference. It goeswithout saying that it is possible to use a winding device with the pinshape and arrangement changed for each U phase, V phase and W phase andto adjust the length and shape of the respective crossover wires toappropriate ones.

When arc crossover wires are adopted, it is possible to further improveinsulation properties by keeping the distance constant in the diameterdirection between the rotation shaft of the rotor 2 and the crossoverwires.

When the winding of the four continuous coils is completed in this way,the four continuous coils are removed from the winding jig, the fourcontinuous coils are then bent by 90° so that each coil is orientedtoward the vertical direction within the vertical plane in the diameterdirection of each coil with reference to the crossover wires 35U2, 35U3and 35U4 as shown in FIG. 7, and it is thereby possible to form fourcontinuous coils that can be assembled in the axial direction as shownin FIG. 5 by setting the length L of the crossover wire to, for example,2×L₃+L₂, while maintaining the crossover wire in a desired shaperegardless of the core layer thickness L₁′ which may be large.

Lastly, as shown in FIG. 8, by forming, in advance, the crossover wires15V2 and 15W2 of the V-phase coil 10V and W-phase coil 10W so as to tiltat different angles φ1 and φ2 in the axial direction with respect to theU-phase coil 10U, it is possible to assemble the four continuously woundcoils corresponding to three phases in the axial direction. Here, aminimum value of φ1 is defined by a spatial insulation distance betweenthe U-phase reference coil 10U and the V-phase coil 10V, and a minimumvalue of φ2 is likewise defined by a spatial insulation distance betweenthe V-phase coil 10V and the W-phase coil 10W.

Instead of this, when the winding end positions of the U-phase coil 10U,V-phase coil 10V and W-phase coil 10W are made to differ from each otherand the coils are bent back by 90° so that all the coils are orientedtoward the vertical direction, the respective crossover wires may bemade to have different heights.

REFERENCE SIGNS LIST

1 Stator

2 Rotor

3 Iron core

4 Input wire

5 Neutral point

10 a to 10 l Coil

10U U-phase coil

10V V-phase coil

10W W-phase coil

15U1 Input wire

15U2, 15U3, 15U4 Crossover wire

15U5 Terminal wire

15V1 Input wire

15V2, 15V3, 15V4 Crossover wire

15V5 Terminal wire

15W1 Input wire

15W2, 15W3, 15W4 Crossover wire

15W5 Terminal wire

20 a, 20 d, 20 g, 20 j Split core

21 a to 21 d Split core back-and-forth adjustment mechanism

22 a to 22 f Fixing pin

23 a to 23 d Winding bobbin fixing section

24 a Nozzle

25U2, 25U3, 25U4 Crossover wire

30 a, 30 d, 30 g, 30 j Split core

31 Winding jig

32 a to 32 f Fixing pin

33 c to 33 d Winding bobbin fixing section

34 Winding Support section

36 Winding Support section

24 b Nozzle

35U2, 35U3, 35U4 Crossover wire

100 Axial gap motor

1. An axial gap dynamoelectric machine comprising: a stator core inwhich continuously wound cons comprising a plurality of coils formed ofcontinuously wound insulation-coated conductor wire are disposed in acircumferential direction with the continuously wound coils of threephases overlapped, wherein with the respective coils being disposed in aradiating shape, the continuously wound coils are configured so that onthe inner diameter side of the coils, the insulation-coated conductorwires are continuously wound to adjacent coils via crossover wires, andthe coils are bent in a vertical direction and the continuously woundcoils of each phase are made to overlap with each other so that thelength of the crossover wires can be adjusted regardless of the corelayer thickness of the stator core.
 2. The axial gap dynamoelectricmachine according to claim 1, wherein when each coil is bent in thevertical direction and continuously wound coils of each phase areoverlapped with each other, neutral points which are winding start endsof the insulation-coated conductor wire in each phase are arranged so asto be adjacent to each other in the inner circumference of the statorcore.
 3. The axial gap dynamoelectric machine according to claim 1,wherein the length of the crossover wire is adjusted using fixing pinsprovided in a winding jig that holds each coil in a radiating shape. 4.The axial gap dynamoelectric machine according to claim 1, wherein whenbending each coil in the vertical direction and causing the continuouslywound coils in each phase to overlap with each other, the crossover wireof the continuously wound coil in the circumferential direction isformed into an arc shape.
 5. The axial gap dynamoelectric machineaccording to claim 1, wherein when each coil is bent in the verticaldirection and the continuously wound coils in each phase are caused tooverlap with each other, the crossover wires in each phase are disposedso as not to cause interference.